Sunflowers - a regenerative crop poised for expansion in the US?
Sunflowers tower over the soil and their fellow grain and oilseed crops this time of year. Routinely reaching heights in excess of 10-feet, their bright blossoms offer a brilliant haven for pollinators, promising a rich oilseed harvest in a few short weeks. Below the ground, researchers document their roots often extend more than 8 feet into the earth, far below the 4-5 foot depth commonly reached by corn, and triple the rooting depth of their most analogous crop from an end-use perspective, soybean (Schlegal et al. 2016). This prodigious growth, both above and below ground, make sunflower particularly intriguing from a climate perspective. From a mitigation perspective, sunflower is well-suited to capture more carbon than the two crops that are currently most dominant on the American agricultural landscape, corn and soybean. From an adaptation perspective, those deep roots make sunflower much more drought tolerant, as well as better nutrient scavengers than the status quo crops, so why isn’t there more sunflower grown in the US?
While sunflower originated in the US, it has seen much broader adoption in Europe, while American production has dropped off in recent decades.
No Market? Multiple market research firms paint a rosy outlook for sunflower, with growth expected in the category over the next 3 to 5 years (here and here). Although readers are probably most familiar with confectionery applications of sunflower, e.g. sunbutter, granola ingredients, or bread topping, about 90% of the sunflower crop goes to oil production, a process that yields both oil and a meal byproduct typically used as livestock feed. This is similar to the dominant use of soybeans, which currently supply the protein fraction of the diet for the 70 billion pounds of pork and chicken meat the US produces each year. Despite sunflowers origins as an American crop, and soybeans’ Eurasian origins, their current distribution is reversed. There are more than 83 million acres dedicated to soybeans in the US this year, but only 1-2 million acres of sunflowers (USDA-NASS 2020). In Europe, there are fewer than 14 million acres planted to soybean, but more than 46 million acres planted to sunflower (FAOSTAT 2020).
Performance does not differ between the US and Europe and has improved steadily over the last 15 years (FAOSTAT 2020).
Is there a yield drag? Some crops perform better in certain regions of the world than others, so does that explain sunflower’s acceptance in Europe and relative abandonment in the US? No. Yields of sunflower in the US and Europe have improved steadily over the last few decades, and the crop yields a little under 2,000 lbs per acre on both continents (FAOSTAT 2020, USDA-NASS 2020). Research conducted in Kansas compared sunflower with soybean and found the crops yielded similarly, but that sunflower had better yields under drought conditions. So, there is no evidence that sunflower is lower yielding than either European grown sunflower or American-grown soybeans.
Further yield improvements possible. 12 Variety trials conducted at the University of Minnesota documented biomass production of 2-3 tons (4,000 to 6,000 lbs) per acre with seed yields of 2,000-2,230 lbs per acre. Oil content of seeds was 42-43%, increasing with higher plant densities. Other variety trials conducted in Missouri in 2006 had yields of up to 2830 lbs per acre. These data suggest sunflower is a promising crop that may be well-suited to support re-diversification of American agriculture, while improving carbon capture, reducing nitrogen leaching, offering greater production in the face of drought conditions, all while maintaining or improving calorie, oil, and nutritional supply currently afforded by soybean in the US.
Sunflowers, a crop originally developed by indigenous people in modern-day Missouri, Iowa, and Minnesota, has all but disappeared from that region over the last 4 decades, and is now produced almost exclusively in the Dakotas.
Infrastructure limits US cultivation. While sunflower appears to be an under-appreciated star from an agronomic and environmental perspective, there are a few challenges hindering its broader adoption. For all of sunflower’s potential, the crop is far more voluminous and less dense than soybeans, weighing only 28 lbs/bu compared with 60. This makes transporting sunflower, either by truck or rail, economically infeasible for any significant distance.This means, local processing is necessary to convert the voluminous seeds into denser meal and easily transportable oil. Unfortunately, there are only 5 processing plants left in the US for sunflower, owned by just 3 companies. These facilities in North Dakota, Colorado, and Kansas limit expansion of cultivation much beyond the Dakotas.North and South Dakota have produced >80% of US sunflower since 1981. Minnesota historically produced sunflower, hosting more than a million acres of sunflower in 1979 and accounting for a third to a quarter of production through the early ‘80s. Minnesota sunflower acreage declined precipitously in the ‘80s from about a million acres to less than 100,000 acres where it has remained for the last 3 decades. In recent years, only about 60,000 acres of sunflower were grown in Minnesota, less than a tenth of the acreage grown in both North and South Dakota. Kansas is now the third leading producer of sunflower after the Dakotas, but it too only grew ~70,000 acres compared with >620,000 acres in ND and >600,000 acres in SD.
While current production is limited, the agronomic performance, nutritional profile, and environmental resilience of sunflower make it a crop worth a second look. With both full- and double-crop varieties available, it is possible to grow in rotation with small grains in many areas of the US. The only barrier to broader adoption is processing infrastructure.
